Propellers, pumps, lift fans, turbines, generators, compressors, grinders, spindles, drive shafts, machine tools, turbo machinery, and any other types of rotating machinery are susceptible to vibration associated with imbalances within the machine. The vibration, if not corrected, can cause the devices to run inefficiently and ultimately fail.
In some aspects, two or more closely coupled and independently rotating machines (e.g., two or more propellers of an airplane or landing craft, two or more lift fans of a hovercraft, etc.) can be used together. When this happens, vibration from one piece of rotating machinery can be transmitted to the other(s) through the structure, which is known as cross-talk or noise. The cross-talk will not prevent the machinery from being balanced; however, the balance corrections being made on one machine will affect the other. If both machines are balanced at the same time, the controllers cannot distinguish between the vibration changes caused by each balancer. This can result in unnecessary balancing cycles, additional time to balance, and an inability to achieve low vibration levels.
Another problem associated with attempting to balance closely coupled machinery is that when cross-talk occurs, and the machines are operating at similar, but not the same revolutions per minute (RPM), signal beating occurs. If the RPM's are too close for the controllers to discriminate between the vibration frequencies, and the level of beating is significant, the controllers will interpret the vibration signal as rising and falling. Thus, the respective controllers will attempt to balance each piece of equipment, including the rising and falling vibration signal. This also results in unnecessary balancing cycles, additional time to balance, and inability to achieve low vibration levels.
Accordingly, there is a need for improved devices, systems, and methods for balancing closely coupled rotating machinery for improving vibration reducing and increasing service life.